reorganize octave_config_info again * build-env-features.sh: Don't include ENABLE_ items in the output. * toplev.cc (find_config_info): New static function. (Foctave_config_info): Put Octave configuration info in the main struct. Put the build system features and build environment info in substructures. Allow searching of all elements by keyword. * __have_feature__.m, doc/interpreter/testfun.txi: Fix name of build features substructure element. * geometryimages.m, interpimages.m, plotimages.m, sparseimages.m, splineimages.m: Use __have_feature__ to check for OSMESA.

%!function r = f1 ()
%!  ls = svd (1);
%!  r = eval ("ls -1;");
%!endfunction
%!function r = f2 ()
%!  [u,ls,v] = svd (1);
%!  r = eval ("ls -1;");
%!endfunction
%!function r = f3 (ls)
%!  r = eval ("ls -1;");
%!endfunction

%!test
%! ## Windows systems can't run "ls -1"
%! if (! ispc ())
%!   assert (f1 (), 0);
%!   assert (f2 (), 0);
%!   assert (ischar (f3 ()), true);
%!   assert (f3 (1), 0);
%! endif